82 Already given in detail in his “Lehrbuch der phys. und pathol. Chemie” (Second Edition, 1889), in the first chapter, “Vitalism and Mechanism.” In the meantime a fifth revised and enlarged edition of Bunge’s book has appeared as a “Lehrbuch der Physiologie des Menschen” (Leipzig, 1901), The relevant early essays appear here again under the title “Idealism and Mechanism.” The arguments are the same. It is often supposed that it is merely a question of time, and that in the long run we must succeed in finding proofs that the whole process of life is only a complex process of movement; but the history of physiology shows that the contrary is the case. All the processes which can be explained mechanically are those which are not vital phenomena at all. It is in activity that the riddle of life lies. The solution of this riddle is looked for, more decidedly than before but still somewhat vaguely, in the “idealism” of self-consciousness and its implications, “_Physiologus nemo nisi psychologus_.” These views have been also stated in a separate lecture: G. Bunge, “Vitalismus und Mechanismus,” (Leipzig, 1886). 83 “Allgemeine Biologie” (2 vols.), Vienna, 1899. 84 Jena, 1903. _ 85 Cf._ especially Verworn’s example of the manufacture of sulphuric acid. See what we have previously said on the “second line” of mechanistic theory, along which Neumeister’s thought mainly moves. See especially p. 198. As regards the “fifth line,” the problem of the development of form in its present phase, there is an instructive short essay by Fr. Merkel (Nachrichten der K. Gesellschaft der Wissenschaften Göttingen. Geschäftl. Mitt. 1897, Heft 2)—“Welche Kräfte wirken gestaltend auf den Körper der Menschen und Tiere?” This essay avoids, obviously intentionally, the shibboleths of controversy. The mechanical point of view and the play with mechanical analogies and models are abruptly dismissed. “If things, which were in themselves susceptible of mechanical explanations, occur in the absence of the mechanical antecedent conditions, then we must seek for other forces to enable us to understand them.” And quite calmly a return is made to the old, simple conception of a “regulative” and a “formative force,” inherent as a capacity _sui generis_ within the “energids,” the really living parts of the cell. The cell-energid carries within it the “pattern” of the organisation, and the partial or perfect “capacity” (“Fertigkeit”) for producing and reproducing the whole organism. But these two forces “make use of” the physico-chemical forces as tools to work out details. So to describe the state of the case is not of course a solution of the problem; it is only a figurative formulation of it. But that, at the present day, we can